Roasted Vegetable Quiche

A roasted vegetable quiche is a savory custard pie built on caramelized vegetables that have spent time in a hot oven. The vegetables brown and soften while the eggs and cream set into a tender filling, and a good crust holds everything together. The key is roasting the vegetables first so they bring real flavor instead of steaming in their own moisture.

Ingredients for Roasted Vegetable Quiche

Zucchini and bell peppers roast down and soften while their edges brown, red onion turns sweet and caramelized, and mushrooms lose their water and concentrate their umami. Olive oil helps everything brown and keeps the vegetables from sticking. Salt and black pepper season the vegetables as they cook. Eggs and heavy cream make the custard that binds the quiche together, while Gruyère cheese adds richness and a subtle nuttiness. Fresh thyme brings an earthy note that pairs with roasted vegetables. A pie crust holds everything and bakes to golden brown.

Why This Roasted Vegetable Quiche Works

Roasting the vegetables first is the difference between a quiche that tastes like vegetables and one that tastes like a vegetable steam bath. High heat dries the surface of each piece so it can brown instead of release water into the pan. The vegetables caramelize, which means their sugars break down and turn sweet and complex. By the time they go into the quiche, they have already given up most of their liquid, so the custard stays creamy instead of watery.

The custard itself is straightforward: eggs thicken as they heat, and cream keeps them tender. The mixture goes into a crust that has been partially baked so it does not turn soggy from the wet filling. You bake the whole thing at moderate heat until the center is just set but still has a tiny jiggle when you shake the pan. This gives you a custard that is custardy, not rubbery.

Mistakes To Avoid

Overcrowding the roasting pan means vegetables steam instead of brown. Arrange them in one layer without touching, and if they do not fit, use two pans. The vegetables will look pale and soft instead of caramelized and golden.

Skipping the pre-bake of the crust leaves you with a soggy bottom crust that never crisps. The bottom stays pale and damp even after the quiche is cooked all the way through because the wet filling hits cold dough.

Baking the quiche too hot or too long turns the custard rubbery and separates the eggs from the cream. The center becomes dense and firm instead of tender, and you may see liquid pooling around the edges.

Adding vegetables that are still wet from roasting dilutes the custard and makes the quiche watery. Let the roasted vegetables cool on a paper towel for a few minutes so any surface moisture evaporates before you layer them into the crust.

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Ingredients

• 1 medium zucchini, cut into 3/4-inch pieces
• 1 large bell pepper, cut into 1-inch pieces
• 1 medium red onion, cut into 1-inch pieces
• 8 ounces mushrooms, quartered
• 3 tablespoons olive oil
• 1 teaspoon salt, divided
• 1/2 teaspoon black pepper, divided
• 1 unbaked 9-inch pie crust
• 4 large eggs
• 1 cup heavy cream
• 1 cup shredded Gruyère cheese
• 2 tablespoons fresh thyme leaves

Step-by-step Instructions

1. Heat oven to 425°F (220°C). Toss zucchini, bell pepper, red onion, and mushrooms with olive oil, 1/2 teaspoon salt, and 1/4 teaspoon black pepper on a large rimmed baking sheet.
2. Spread vegetables in a single layer without touching. Roast at 425°F (220°C) for 20 to 25 minutes, stirring halfway through, until vegetables are soft and browned at the edges.
3. Remove from oven and let vegetables cool on the sheet for 5 minutes, then transfer to a paper towel to absorb any surface moisture.
4. Place pie crust in a 9-inch pie pan. Prick the bottom all over with a fork. Pre-bake at 375°F (190°C) for 8 to 10 minutes until the bottom is set but not brown, then remove and let cool for 5 minutes.
5. In a bowl, whisk together eggs, heavy cream, 1/2 teaspoon salt, 1/4 teaspoon black pepper, and fresh thyme leaves until smooth.
6. Scatter roasted vegetables and Gruyère cheese evenly into the crust, then pour egg mixture over the top.
7. Bake at 350°F (175°C) for 35 to 40 minutes until the center jiggles just slightly when you shake the pan and an instant-read thermometer inserted into the center reads 160°F (71°C).
8. Let the quiche rest at room temperature for 10 minutes before slicing and serving.